blow by advice needed (1 Viewer)

Joined
Jun 1, 2006
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Port Coquitlam
 
 
Once again, I look towards those wiser than I for assistance, and I thank you in advance.
So here is the issue:
I've noticed an increase in blow by and I also noticed an increase in oil level depletion (I can't say burning up because I'm sure it's not getting burned).
I've added a turbo to my truck (link in my signature) and made some alterations:
https://forum.ih8mud.com/diesel-tec...turbo-still-working-out-bugs-suggestions.html

here is the new issue:
I've lost about 1.5-1.8L of oil in 4000km of driving through blow by. I've figured out it's not burned up because the glow plugs have a normal amount of carbon deposit and the underside of my truck is very oily.
now I've been running the truck with 13lbs of boost for a while and that's when I've noticed the increase in blow by. I've tested my compression today and it's the same as it was when I reinstalled the turbo and increased the boost. So the compression is 420,410, 420,420. If the rings were dying the compression would be lower. So what do you think is causing the extra blow by and oil consumption?
If the blow by is casued by the increased boost that would have an effect on oil pressure (if it's pushing by the rings and causing that) but the pressure is normal and holding steady (I'm using an isspro guage not the factory one), so this is where I'm confused and wondering what the hell is going on. I've turned the boost down to 10 and will drive it like that for a bit to see what happens but I would love some ideas/opinions/suggestions.
Thanks guys.
 
Joined
Jul 4, 2006
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Montreal
 
 
I always lose some oil through blow by until the level goes down to around half the marks on the level stick. Once there i stop losing oil and no more drip through the blowby.

I would suggest to let the level go down, Obviously not passed the low mark, and see if it stops somewhere between high and low mark.
 
Joined
Sep 28, 2002
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Kamloops, BC Canada
 
 
 
 
Mat;

A litre of consumption over 5000 kms is normal.

So, the extra may depend on other factors such as the mileage of your engine, the type of oil you're using etc. On my own 3B, I noticed a significant increase in oil loss as the oil aged - the more mileage that was on it, the more likely it was to disappear.

Valve guide seals are rarely an issue with diesels as their is no real vacuum developed in the intake manifold, but the 3B is a little bit of an exception due to the intake arrangement - but I have not seen one that has had any significant oil consumption from valve sealing, even when they're pushing some really high mileage.

~John
 
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thanks guys,
I'm running Rotella 15/40, have about 4000km on it (I change it at 5000km religiously). Until now the engine has not consumed or lost any more than 1/2 a litre of oil between oil changes. Now with the added boost of the turbo running perfectly and at max 13-14PSI I've lost 2 Litres. That's what concerns me, the drastic change.
I have done a leak down test before this (haven't gotten around to doing it recently but I will) and I have little of a leak on the valves, exhaust if I recall correctly, and that's it.
Should I be worried? any other tests that I can do to narrow down possible problems/issues?
 
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Dec 29, 2006
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Abby
 
 
Mat, you will likely find the Castro Tection Extra a bit thicker. You might consider trying it to see if it makes any difference on your 3B. My OEM pressure gauge with the Tection Extra reads about 1/4 higher on cold start-up and about an 1/8 higher hot than Delo or Rotella. It does have a high cold pour point than the other two. For that reason, I do not run it during the winter. You usually can find it for a very good price at Western Star Sterling if you buy multiple buckets of it.
 

BreckenridgeCruiser

I break things.
SILVER Star
Joined
Aug 14, 2006
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Oceanside and Encinitas, CA
 
 
I have the same issue, but I see loss after the mid mark on the dipstick. I have to powerwash the bottom of the truck to check it again and see if I just have a nasty rear main leak. Once I take care of any seal issues, where else could this oil be going?
 
Joined
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Read your other post who did the turbo rebuild maybe you are pushing oil through the turbo seals.
oil through the turbo seals? that would cause it to go either into the intake or the exhaust, not the blow by tube. Unless I'm missing something.

What seals are there between the combustion chamber area and the blow by chamber?
Or more importantly what would cause increased blow by but still maintain good compression?

I could run a thicker oil but I don't want to put a band aid on a severed hand. Besides, when cold, the oil pressure is 40-50PSI at idle (I have an IssPro guage on top of the factory one), when hot at idle I have about 10-15PSI. On the highway when hot at 2400RPM it's at 50-60. When I just gently play with the pedal between fulll 13PSI boost and dropping it down to about 4PSI (letting off the pedal just a touch) I still maintain the same RPM and the oil pressure does not change at all.

Has anyone with an aftermarket turbo add on encountered this before and found a reason.

In the end if no damage is being done to the engine then it's not a big deal but if I'm quickly moving in the direction of something going BANG while I'm in the bush 2 days drive from some village I want to deal with this now.

thanks
 
Joined
Feb 24, 2006
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Acton Vale
 
 
I have the same problem than you and I rebuild all the motor and put a turbo on it and it's always blow oil true the blow by tube. Maybe a little bit more with the turbo. You can see the fume when It's idle at a corner.

Rebuild the head, piston, ring, and bearings, nothing change. Change the head gasket, not better. change some seal and gasket... always the same. I think maybe I have a crack in my head that do that. My compression ration is between 400-500psi cold.

The motor do this since 20 years.. maybe more and will do that for an other 20 years, I stop searching for this trouble.
 
Joined
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Mat, the sure way to confirm that all the disappearing oil is going because of blow-by is to fit a simple catch can to collect the oil. Just compare the amount of oil collected against the oil poured in. Also, I don't think 1.5L in 4000 kms would carbon up your glow plugs.

I just re-read John's post about the increase of oil loss as the oil aged. I have noticed the same thing with the TD4.2 on my 5 spd. It doesn't use any oil until I hit 3000 kms. Then it starts to disappear. I think most of the oil finds its way through a leaky rear main seal. The TD4.2 on the auto is similar but looses far less oil - about 1/3L in 5000kms. It too has a leaky rear main seal. The other difference is the 5 spd is running 2600 rpm at 110kph while the auto is running just under 2200 at 110kph. I've noticed if I keep the speed and rpms down on the 5 spd that oil loss is minimal. It is hard to do when you got 800 kms to drive. I am hoping 33" tires will help.
 
Joined
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If the blow by is pushing out oil it should be very noticable on your front drives and there should be a oil spot on the driveway.... throw a catch can under your blow pipe and see if you are collecting the amount of oil you claim to be losing if not you are burning it internally.

canucksafari you type faster than me my same thoughts as above
 
Last edited:
Joined
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guys, I've already established where it's coming from, I know how much I'm loosing and I've done the can thing. Now I need to know what causes it. Like I said, what would cause good compression and higher then normal blow by? a rapid increase over a short period of time is not normal. a gradual one is understandable.
I know some engine consume or blow oil out more than others but in this case I've gone from 1/2 a litre loss per oil change to 2 and it's not burning up, 3/4 of that is going out the blow by. I've got a couple small spots where it's leaking gradually but those are very minimal.
 
Joined
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Well you could always pull off the turbo and see if things change if you are going to lose sleep over the engine going caboomb or just live with the fact she's going to spit a little more oil out the blowby.
Keep the catch can on it that way you dont mess up the driveway
 
Last edited:
Joined
Jun 4, 2008
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Picton, Ontario, Canada
 
Oil consumption issues on an engine within spec can sometimes be caused by glazed cylinder bores. Some claim here that certain oils are responsible. Maybe you had an extreme heat event. Are you running an EGT guage or monitor? There are some previous posts about cylinder glazing that might help you to understand others experiences. Sometimes the only thing you can do is open it up to install new rings and clean the bores.

As an aside, I have had this condition in a VW TD 1.6. A new set of rings, hone , and valve guides/new valves/ seat renewal reduced oil consumption from 5.0 litres per 2000 km to 0.7 litres/ 2000 km! And yes, the guides were seriously worn (bronze). The rings were done too. The bores were worn to just a hair over spec so I decided to install rings only. If you go this route make sure that you use a brush hone. Brush Reasearch makes hones sized to every application. Throw away your old three stone unit! They are junk. These brush hones really work!

Seat in the rings with a fast warm up then immediately full load, high cylinder pressures as there is a very limited window for ring seating before you are going to glaze the bores again. Don't baby the rebuild!
 
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....Like I said, what would cause good compression and higher then normal blow by? ....
Loose ring lands in the pistons, ring wear, bore wear? At slow cranking speeds and/or driving low/no boost the rings are able to maintain tension/seal, but add 12psi and there is ring flutter and leakdown. Doubt it would lead to the engine going 'boom'. Will it cause the bottom end to wear/fail faster - maybe.
 
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that's the type of info I was looking for. Thanks guys! It does make sense that at lower pressure and slow cranking the wear wouldn't be as noticeable, where at 2400RPM and 12+PSI on top of the regular compression I could see some slop.
I'll do some more test over the next few months if I find something interesting I'll let you know.
 
Joined
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Turbos push air and exhaust into the crankcase through their oil drain, if your breather is struggling to keep up the extra flow from the turbo could push it over the edge.

Are your valve seals okay? The only time my diesel has ever used oil the valve guides and seals were leaking oil into the intake and exhaust ports. In my experience even low compression on a diesel won't make it burn oil in the same way a petrol engine does.
 

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